How do I calculate employee commuting emissions for a factory with 200 workers?
Run a short survey asking each worker's usual mode and one-way distance, scale the answers up to all 200 workers, then multiply kilometres per mode by working days and a per-km factor. This is the distance-based method for Scope 3 Category 7. Label the result as a survey-based estimate.
What to ask in the survey
Keep it to one screen or one paper slip. Ask supervisors to collect slips by shift; response rates are higher than with email.
- Main mode of travel: walk or cycle, two-wheeler, car, shared auto, public bus, company bus.
- One-way distance from home to the factory, in km.
- If by car or two-wheeler: travelling alone or with others.
- Days a week at the factory, and shift.
Turning answers into tonnes
Use published per-km factors where you can, such as the India GHG Program road transport factors. The example derives factors from fuel economy and IPCC fuel factors, with the assumptions stated.
- Scale respondents up to the full headcount, mode by mode, if response is below 100%.
- Kilometres per mode = workers x round-trip km x working days.
- Emissions = km x factor per km for that mode (per passenger-km for buses).
- Add the modes. Walking and cycling count as zero.
What is not Category 7
- A company-owned or company-fuelled staff bus: Scope 1, from its fuel invoices.
- A hired bus or cab contract paid by the company: usually Category 7 or a purchased service; follow one rule consistently.
- Business trips: Category 6, not commuting.
Worked example: 200 workers, 300 working days (estimate)
- Mode split scaled from survey: 110 two-wheeler (10 km one way), 20 car alone (15 km), 50 bus (12 km), 20 walk or cycle
- Assumed factors: two-wheeler 2.31 kg CO2/L petrol / 45 km/L = 0.0513 kg/km; car 2.31 / 15 km/L = 0.154 kg/km; bus 2.68 kg CO2/L diesel / 4 km/L / 40 passengers = 0.01675 kg per passenger-km
- Two-wheeler: 110 x 20 km x 300 = 660,000 km x 0.0513 = 33,880 kg
- Car: 20 x 30 km x 300 = 180,000 km x 0.154 = 27,720 kg
- Bus: 50 x 24 km x 300 = 360,000 passenger-km x 0.01675 = 6,030 kg
- Total: 33,880 + 27,720 + 6,030 = 67,630 kg CO2, about 67.6 tonnes a year
Fuel economy and bus occupancy are assumptions; replace them with published per-km factors or your own data. The two-wheeler figure uses the unrounded 0.05133 kg/km.
What Senseible does here
Senseible does not run commuting surveys or calculate Category 7. If the company pays for a staff bus, it reads those fuel slips and counts them in Scope 1.
Sources: GHG Protocol Technical Guidance for Calculating Scope 3 Emissions (2013), Category 7, 2006 IPCC Guidelines, Volume 2 Energy (petrol and diesel factors)
Last reviewed 2026-10-15.